Abstract Neuronal cell types are the building blocks of brain function and differences between cell types are critical to understanding nervous system disease. New genetic and genomic resources are increasingly available for identifying and manipulating specific cell types in the mouse. We will create a unified gateway to these reagents and a platform for integrating and sharing data obtained with them to enhance progress on the difficult problem of identifying the neuronal cell types of the mammalian brain. We will implement a searchable, freely shared open source database of resources and experimental results. We will annotate the anatomical location of targeted cell types within each of ~90 existing driver/reporter strains by aligning individual sections to the Allen Brain Reference Atlas and will develop new strains using a novel lentiviral enhancer trap strategy in mice. For a subset of cell types we will perform genome-gene expression profiling to enhance insights from this unbiased metric of relationships between neuronal cell types. We will integrate the cell type database and improved atlas viewer with tools for viewing cell type-specific morphology, physiology and gene expression data, and will link these data with other available brain atlas and genomic databases. The ability to freely search and compare cell-type specific phenotypes and gene expression data will enable members of the scientific community to develop specific hypotheses about the molecular bases of specific cellular phenotypes and to improve schemes for classifying neuronal cell types.